CT screens in smokers ‘reduce risk of lung cancer mortality'

US researchers systematically reviewed 24 randomised controlled trials or cohort studies that included 368,713 asymptomatic and former adult smokers who had at least a 30-pack-year history. Studies were categorised as good, fair or poor by researchers. Lung-cancer mortality rates for both comparison groups (low-dose CT vs. chest radiography or usual care) after the study follow-up period were measured. The mean follow-up periods ranged from 34 months to 6.5 years. No trials reported data on LDCT lung cancer screening in women or in different racial or ethnic populations.

The results

One good-quality trial (n = 53,454) of high-risk smokers showed that low-dose CT compared with chest radiography conducted over three screenings reduced lung cancer mortality by 20%. Three smaller (n = 2472, 4099, and 4104) European trials of fair- and poor-quality included high-risk participants and showed no benefit associated with low-dose CT screening, compared with no low-dose CT screening. A meta-analysis of three fair- or good-quality trials showed a relative risk of lung cancer mortality of 0.81 for low dose CT vs normal therapy.

What this means for GPs

The researchers concluded that there was ‘strong evidence’ low-dose CT screening can reduce lung cancer and all-cause mortality, but warned that ‘the harms associated with screening must be balanced with the benefits’.